Ghosts in my TPI setup! Please help.
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Ghosts in my TPI setup! Please help.
I have been chasing a funky problem for awhile now. Basically, when I get above half throttle my truck starts to pop like its misfiring or going lean. Now, if I really get on it in first gear it does it the most. If I am only going 30mph and in 3rd gear, and I floor it, it doesn't pop, but doesn't have much pep (partly due to the low speed and 1:1 ratio of the gear). It seems the higher the RPM or more the load, the more the popping. This makes me think its going lean.
My combo is this: 350 with a TPI. Custom chip (via me), painless harness. Th-350 trans, 4.10 gears. If you request any more info I'll be happy to provide.
As I work for a parts house (at least when I am not in school), I can replace things cheaply if not for free. Before I began parts replacement I checked the basics like base timing (set at 6 degrees) and fuel pressure (currently at 40PSI).
Over time, pretty much EVERYTHING has been replaced. When it first began doing this I replaced the fuel pump and filter. No change. I then checked and replaced the fuel pressure regulator diaphram. No change. At that point I though that it might be going lean due to inaccurate air readings. I swapped in a friends good MAF and there was no change.
My spark appeared to be a bit weak so I put in a new coil and module and a wireset and while the spark looked a bit more powerful, the same problem was occuring.
At that point I decided to toss in a new computer and MAF power relay.. After that the truck ran GREAT! So I drove it down to school and within a few days it began acting up again. As it was free, I tossed in a new ECU and there was no change. As it was seeming to act up at a certain throttle point, I though my TPS might have a flat spot. I couldn't see one through my scanner but I decided to put in a new TPS anyways. After that, the truck ran GREAT!
Two days later, same problem occuring. I really have no idea what it could be. It seems to get better after random parts replacement. I also changed out the oxygen sensor as it was time. The idle smoothed a bit but the main problem persisted.
I am about ready to ditch the whole ECU system and go with an aftermarket unit. Before I drop that sort of money, does anyone have any ideas?
Thanks for your help.
Also, what are the part numbers for the MAF Power and Burn-off relays. I have searched this board but have found conflicting results as to if these are interchangeable. Some people say they are totally interchangable, others say no they aren't. Any definitive answer? I believe my power relay is currently an MR22. However the listed part number now appears to be MR82. Could this be the sourse of my problem?
** Also, I see many 85-89 MAF's listed for sale, but have read that an 85 MAF is not compatable with any other year. Can someone explain this? I am running an 85 MAF on my systems. I notice they are different part numbers. Does anyone have experience with this?
My combo is this: 350 with a TPI. Custom chip (via me), painless harness. Th-350 trans, 4.10 gears. If you request any more info I'll be happy to provide.
As I work for a parts house (at least when I am not in school), I can replace things cheaply if not for free. Before I began parts replacement I checked the basics like base timing (set at 6 degrees) and fuel pressure (currently at 40PSI).
Over time, pretty much EVERYTHING has been replaced. When it first began doing this I replaced the fuel pump and filter. No change. I then checked and replaced the fuel pressure regulator diaphram. No change. At that point I though that it might be going lean due to inaccurate air readings. I swapped in a friends good MAF and there was no change.
My spark appeared to be a bit weak so I put in a new coil and module and a wireset and while the spark looked a bit more powerful, the same problem was occuring.
At that point I decided to toss in a new computer and MAF power relay.. After that the truck ran GREAT! So I drove it down to school and within a few days it began acting up again. As it was free, I tossed in a new ECU and there was no change. As it was seeming to act up at a certain throttle point, I though my TPS might have a flat spot. I couldn't see one through my scanner but I decided to put in a new TPS anyways. After that, the truck ran GREAT!
Two days later, same problem occuring. I really have no idea what it could be. It seems to get better after random parts replacement. I also changed out the oxygen sensor as it was time. The idle smoothed a bit but the main problem persisted.
I am about ready to ditch the whole ECU system and go with an aftermarket unit. Before I drop that sort of money, does anyone have any ideas?
Thanks for your help.
Also, what are the part numbers for the MAF Power and Burn-off relays. I have searched this board but have found conflicting results as to if these are interchangeable. Some people say they are totally interchangable, others say no they aren't. Any definitive answer? I believe my power relay is currently an MR22. However the listed part number now appears to be MR82. Could this be the sourse of my problem?
** Also, I see many 85-89 MAF's listed for sale, but have read that an 85 MAF is not compatable with any other year. Can someone explain this? I am running an 85 MAF on my systems. I notice they are different part numbers. Does anyone have experience with this?
